Add sample PGO integration test to cover profile annotation and inlining.

[danielcdh]

Summary

The patch makes the integration test cover major sample PGO components.

[davidxl]

test/CodeGen/pgo-sample.c

4

using a a negative threshold to make sure regular inline heuristic does not kick in?

Also how about new PM?

28

SHould this be 'CHECK-NOT: call' as bar is also inlined?

[danielcdh]

Integrate David's comment and add new PM test.

[danielcdh]

test/CodeGen/pgo-sample.c

28

There is still call to baz. Explicitly added CHECK-NOT call bar.

[davidxl]

lgtm

[danielcdh]

the patch was reverted as it breaks on certain platforms (e.g. http://lab.llvm.org:8011/builders/clang-hexagon-elf/builds/10088/steps/ninja%20check%201/logs/FAIL%3A%20Clang%3A%3Apgo-sample.c)

test/CodeGen/Inputs/pgo-sample.prof

-bar:100:100
- 1: 2000
+bar:1000:1000
+ 1: 1000
+ 2: 0
+foo:1000:1000
+ 1:bar:1000
+  1: 1000
+  2: 1000

test/CodeGen/pgo-sample.c

 // Test if PGO sample use passes are invoked.
 //
-// Ensure Pass PGOInstrumentationGenPass is invoked.
-// RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample.prof %s -mllvm -debug-pass=Structure -emit-llvm -o - 2>&1 | FileCheck %s
+// Ensure Pass SampleProfileLoader is invoked.
+// RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample.prof %s -mllvm -debug-pass=Structure -mllvm -inline-threshold=0 -emit-llvm -o - 2>&1 | FileCheck %s
 // CHECK: Remove unused exception handling info
 // CHECK: Sample profile pass
+
+void baz();
+
+// CHECK-LABEL: @callee(
+void callee(int t) {
+  for (int i = 0; i < t; i++)
+    baz();
+}
+
+// CHECK-LABEL: @bar(
+// cold call to callee should not be inlined.
+// CHECK: call void @callee
+void bar(int x) {
+  if (x < 100)
+    callee(x);
+}
+
+// CHECK-LABEL: @foo(
+// bar should be early-inlined because it is hot inline instance in profile.
+// callee should be inlined because it is hot callsite in the inline instance
+// of foo:bar.
+// CHECK-NOT: call void @callee
+void foo(int x) {
+  bar(x);
+}